This invention relates to a glass fiber reinforced propylene-ethylene copolymer base resin composition which is useful as an injection molding material and is particularly suited for automobile instrument panels.
Automobile instrument panels have been produced by injection molding of various resins such as ABS resin, glass fiber reinforced ABS resin, polycarbonate resin, polyphenylene oxide resin and polypropylene resin containing talc. However, such conventional resins as the instrument panel molding materials are not fully satisfactory in all aspects. For example, dissatisfaction remains in moldability, resistance to heat distortion or impact resistance, or in an economical aspect.
Polypropylene resins have good and balanced physical and chemical properties and are available at relatively low prices. Accordingly polypropylene resins are widely used as injection molding materials for various parts including automobile parts. For some uses where high rigidity is required of the moldings it is customary to add reinforcing fillers to polypropylene resins, and glass fiber reinforced polypropylene resins are already used when very high rigidity is required.
Automobile manufactures have made trials of glass fiber reinforced polypropylene resins as the injection molding material of instrument panels with particular interest in low prices and excellence in heat distortion resistance of polypropylene resins. Until now, however, fully satisfactory results have not been obtained yet. Rather, it has become evident that conventional glass fiber reinforced polypropylene resins are insufficient in impact resistance, and particularly in surface impact strength when molded into large-sized and intricately shaped members such as automobile instrument panels.